Hard wires smoke alarms with heat detectors?

[ritelec]

Correct me if I'm wrong and please confirm if correct. When installing heat detectors interconnected with 120v smoke alarms, the neutral gets switched through the heat detector (I believe ??).

If so How is that wired? The neutral connections between the heat detector and the smoke alarm. The smokes get wired to the interconnected hot and interconnected neutral. If I take from that neutral from the smoke and run to the heat (2 wire for switch) then back to the neutral what's it switching?? both sides of the heat detector switch are common and connected to the smoke neutral.(I'm missing some thing???)

Or does the neutral feed get switched through the heat detector and then feed the smoke alarms, ?? But then the smokes wouldn't have neutral and be powered.. please enlighten me.

Two other questions, for garage and attics.... what type of heat detector? Is there a special rate of rise or something???
AND if swapping out existing smokes .... do the heat detectors go bad and should get swapped too?? (I would think not but confirming).

Thank you

 

[ritelec]

I do see interconnected 3 wire heat alarms on line now.... but still curious how to wire up a 2 wire heat detector to the smoke alarm system. Thank you

 

[gadfly56]

I do see interconnected 3 wire heat alarms on line now.... but still curious how to wire up a 2 wire heat detector to the smoke alarm system. Thank you

Standard 2-wire heat detectors are not listed to be installed with smoke alarms. How would that work even in concept? A fire alarm panel circuit is designed to accept a shorting device as an input (manual pull station, heat detector). Nothing good will come of putting a shorting device on a household 120VAC branch circuit.

 

[ritelec]

I don't know ?? In a town house last year I actually removed a two heat from the garage and installed a three wire smoke. There is also a two wire heat in a utility closet that I left alone.

From figuring it out at the time the switching of the neutral made sense but I forgot scantly how it was wired.


Reason for my question is someone called today and wants 5 smokes replaced and said there's a heat in the garage and attic.

Was thinking about the townhouse I saw last your and it was like the Low voltage detectors I see and was rated for 120v.

I don't doubt it's not approved but wondering now why all these town houses with two wire heat detectors were approved.

 

[hbiss]

They do, I believe, make a relay for interfacing 3 wire smokes with a fire panel. It would be possible then to wire the heat detectors after the relay. But you say there was no fire or security panel?

Never thought about it but if you short the red interconnect wire to the hot will all the smokes sound? If not how about to the neutral? Could be this is what somebody did using a LV heat detector. I would just replace the heat detectors with smokes if all the wiring is there.

I don't know if the residential building code even allows heat detectors with interconnected smokes.

-Hal

 

[ritelec]

It just came to me I think. Neutral goes to heat return to the red. I think.

 

[ritelec]

Replace with smokes. I agree. Or these new 3wire heat alarms